U.S. Pat. No. 6,684,897 concerns a sub sea actuator and method that includes all moving components mounted in a compact, concentric configuration. The sub sea actuator is highly reliable and will operate at depth even with zero valve body cavity pressure. A preferably cup-shaped spring pusher is provided in telescoping relationship to the hydraulic chamber. A piston position indicator is provided which is connected externally to the hydraulic piston cylinder to avoid the possibility of hydraulic leaks due to the piston indicator. A manual override may be provided with a manual override indicator. The manual override indicator has a shorter travel length than the manual override operating stem in order to reduce the overall length of the manual override assembly. The driving stem provides a removable connection to the hydraulic piston from the top of the actuator housing and a quick disconnect permits disconnection of the driving stem from the valve stem. In a preferred embodiment, upper and lower t-slot connections are utilized in the driving stem assembly. In a preferred embodiment, two back seat valves are removable secured to the driving stem to engage respective seats and provide additional sealing around the driving stem so as to prevent leakage between the valve chamber and actuator housing chamber. The high tension spring does not need to be removed to perform maintenance and all wear items and seals are readily accessible. Change or replacement of the stem packing is made from the top of the bonnet to avoid disassembling the bonnet to valve body connection. Pre-load bolts are used to adjustably preload the tension in the return spring. The height/weight of the actuator is significantly reduced as compared to prior art sub sea valve actuators.
EP 0 192 973 A1 describes a fail-safe valve actuator that includes a hydraulic piston and cylinder for driving the valve stem and gate member of a gate valve into a first flow control state responsive to sufficient pressure delivered by a fluid or gas supply line. Upon failure or other loss of sufficient control line pressure, a volute spring drives the cylinder, and hence the stem and gate member, axially outward resulting in the valve being moved into a second flow control state.
GB 2 315 114 concerns a valve actuator that includes a hydraulic cylinder and rod mounted on a housing and connected to the valve stem. Two guide rods are disposed between a fixed plate and an interface plate such that a guide plate can move along the rods. Each rod is surrounded by a spring, which has one end abutting the fixed plate while the other end abuts the guide plate to bias the guide plate away from the fixed plate. The guide plate is adapted to transmit movement of the guide plate to the valve stem, movement of the guide plate being transmitted to the valve stem only when the guide plate is moving in a direction away from the fixed plate. Movement of the rod is transmitted to the valve stem only when the rod is moving in a direction toward the cylinder.
EP 0756118 concerns a fluid control system, and its valve assemblies, are used to control the feeding of fluids accurately by operating opening and closing valves promptly and accurately, for the manufacture of semiconductors, magnetic thin films, biotechnical products, and other products. The fluid control system comprises a principal control line (L) and plural branch control lines (L1, L2, . . . ) for feeding plural types of fluid (G1, G2, . . . ) into a processing device (C) coupled to the principal control line, and plural valve assemblies (V) incorporated in the branch control lines (L1, L2, . . . ) for switching the fluids (G1, G2, . . . ) supplied into the processing device (C). Each of the valve assemblies (V) comprises a fluid drive valve (V′) having a fluid pressure actuator (1), and an electromagnetic valve (V″) integrally attached, in single housing, substantially without hoses, to the fluid drive valve (V′) to feed a working fluid (A) into the fluid pressure actuator (1).
EP 0136 567 relates to a seat valve (5) for a tube (1) which on the inner side has a valve seat running inclined to the tube axis, opposite and coaxially to which seat valve there is a tube connection piece (4) for the connection of the seat valve (5). This seat valve (5) contains a valve ram (6) whose projecting end carries a valve plate (7) which abuts directly in its closing direction on the valve seat (3) and in its open position is located opposite the valve seat (3) and separated therefrom. A control chamber in the valve housing (10, 11) is limited on the one hand by the control piston (24), which is connected to the valve ram (6) and can be acted upon by the medium contained in the tube against a restoring spring force. On the other hand, a control opening (14) opens into the valve chamber. The control piston (24) is guided in a cylindrical part (10) of the valve housing. A side of the piston facing the control opening (14) is split into two regions, namely into a starting region (28), which is in open connection with the control opening (14) in the open position, as a somewhat larger surface than the effective compression surface of the valve plate (7) and, when acted on by the medium, raises the control piston (24) from the cylinder cover (13) against the force of the return spring (26), and into a cut-in region (29), which is separated from the control opening (14) when it is in the open position and is likewise acted upon by the cylinder cover (13) after raising of the control piston (24).
U.S. Pat. No. 4,230,299 concerns a pressure balanced gate valve mechanism wherein a closed loop fluid interchange system interconnects the valve actuator stem area of the valve mechanism with the pressure balancing stem area and functions to accomodate volumetric changes to prevent the development of a hydraulic lock that might otherwise prevent or retard opening and closing movement of the valve mechanism. Internal back-face seating arrangements with combination metal-to-metal and elastomeric sealing elements establish seals between the valve stem and bonnet at one gate position and between the pressure balancing stem and valve body structure at the opposite gate position. An externally threaded portion of the valve bonnet is receivable within internally threaded receiver openings of a plurality of different actuator systems, including manual, mechanical, hydraulic and pneumatic actuator systems. The actuator systems are field interchangeable with the valve in service and under pressure. The valve mechanism is capable of being hydraulically energized by portable hydraulic equipment for moving the valve mechanism to a predetermined position in the event the primary drive system should become inoperative for any reason.
WO 2005/098297 concerns a valve, actuator and control system that allows minimizing the size of the actuator and operation of the control system in a manual mode that automatically prevents accidental operation by pipeline pressure is disclosed. The actuator uses gas pressure from the pipeline to power the actuator. In the event gas pressure is unavailable, a pair of manual hand pumps are incorporated to allow operation of the actuator and valve.